Electronically Driven Regioselective Iridium-Catalyzed C-H Borylation of Donor-?-Acceptor Chromophores Containing Triarylboron Acceptors.

ABSTRACT: We observed a surprisingly high electronically driven regioselectivity for the iridium-catalyzed C-H borylation of donor-?-acceptor (D-?-A) systems with diphenylamino (1) or carbazolyl (2) moieties as the donor, bis(2,6-bis(trifluoromethyl)phenyl)boryl (B(F Xyl)2 ) as the acceptor, and 1,4-phenylene as the ?-bridge. Under our conditions, borylation was observed only at the sterically least encumbered para-positions of the acceptor group. As boronate esters are versatile building blocks for organic synthesis (C-C coupling, functional group transformations) the C-H borylation represents a simple potential method for post-functionalization by which electronic or other properties of D-?-A systems can be fine-tuned for specific applications. The photophysical and electrochemical properties of the borylated (1-(Bpin)2 ) and unborylated (1) diphenylamino-substituted D-?-A systems were investigated. Interestingly, the borylated derivative exhibits coordination of THF to the boronate ester moieties, influencing the photophysical properties and exemplifying the non-innocence of boronate esters.

SUBMITTER: Rauch F 

PROVIDER: S-EPMC7497074 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature